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Comment by wlesieutre | Hacker News Reader

Is it sucking up any more data than other grocery stores have been doing basically forever by requiring your membership card to get sale prices?

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It was a lot easier to put in someone else's phone number than someone else's prime account.

Back in the day we used to hold "store card swapping parties" where you'd bring your store card, drop it in the pile, and then everyone randomly picks a new one. Do it about once a month.

Now of course the store cards are tied to apps that give you coupons on things you buy, so it's more in your interest not to mess with them.

Coupons were fun back in the day, if 20+ people were using the same store card phone number it was like winning the lottery: "You have a free sandwich!"

Much harder to do that with phone apps, alas.

I assumed they look at credit cards too, and swapping store cards wouldn't trick them unless you're paying cash. But maybe the number of people who do that is so small that stores haven't cared to catch it.

I don't necessarily think that is technically feasible. At least in the US, they have to be PCI compliant, and I think of that is they cannot store a credit card number. In addition, Chip and pin works differently than a credit card number, as the purchase is tokenized versus to an account number, making cross purchase correlation more difficult.

Merchants can store the account holder's name and the card's last 4 digits, which is pretty much all that is needed to correlate transactions.

This was back in college when we mostly paid cash.

That assumes you have to put in valid data for that. In that case, you are just "Customer #12345" versus a person they can correlate against.

If you have ever paid with a credit card, then the store likely knows exactly who “Customer #12345” is. Stores are tracking purchases this way whether there’s a loyalty account or not.

Discussion of this: https://www.creditcards.com/credit-card-news/retailer-data-t...

So I just read through the article, it mentioned credit card companies knowing that, not the retail store.

I mentioned it in another comment, but the combination of PCI compliance and the use of chip+pin make it difficult for retailors to use credit cards to track an individual, but the credit card company can.

However, if the retailer then goes back and purchases the data from the credit card company, I agree, they will know who "Customer #12345" is with regards to the person.

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